Quick Hits

Episode 4: Vertical Supports, Firestopping & Plenums (720.19 – 720.22)

SLIDE 1 (HOOK / COVER) ⚡ NEC Quick Hit: Vertical Support & Plenums (Part 4 - Article 720)  ⚡ 

Running low-voltage risers up multi-story buildings or routing cables through air-handling spaces? Article 720 outlines strict vertical support and plenum rules. Let's finish Article 720! 👇

SLIDE 2 (VERTICAL RACEWAY SUPPORTS) Securing Riser Cables:

• The 100-Foot Rule: Limited-energy cables and conductors in vertical raceways exceeding 30 m (100 ft) must be supported at the top and with intermediate supports at intervals not exceeding 30 m (100 ft).

• Approved Support Methods: Use insulating wedges, support boxes, or 90-degree offsets with double-supported runs.

SLIDE 3 (FIRESTOPPING & AIR-HANDLING PLENUMS) Preventing Fire Spread in Ducts & Plenums:

• Firestopping: Openings around electrical penetrations through fire-rated walls, floors, or ceilings must be firestopped using approved methods.

• Plenum Spaces: Limited-energy cables installed in other spaces used for environmental air (plenums) must be specifically listed for air-handling use (low smoke/fire resistant).

SLIDE 4 (WRAP-UP) 💡 Apprentice Pro-Tip:

Never run limited-energy systems through dust, stock, or vapor removal ducts (or commercial kitchen ventilation shafts). Keeping low-voltage wiring out of hazardous airstreams prevents catastrophic fire propagation!

💬 Save this post for your final code review on limited-energy and low-voltage installations! 🔗

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